add 5;137;169;191;231

Author: leopsidom

137.single-number-ii.rs

@@ -0,0 +1,52 @@
+/*
+ * @lc app=leetcode id=137 lang=rust
+ *
+ * [137] Single Number II
+ */
+
+// @lc code=start
+use std::collections::HashMap;
+
+impl Solution {
+    pub fn single_number(nums: Vec<i32>) -> i32 {
+        Self::bit_manipulation_sol(nums)
+    }
+
+    pub fn hashmap_sol(nums: Vec<i32>) -> i32 {
+        let mut map = HashMap::new();
+
+        for num in nums {
+            if let Some(v) = map.get_mut(&num) {
+                *v += 1;
+            } else {
+                map.insert(num, 1);
+            }
+        }
+
+        for k in &map {
+            if *k.1 == 1 {
+                return *k.0;
+            }
+        }
+        
+        0
+    }
+
+    pub fn bit_manipulation_sol(nums: Vec<i32>) -> i32 {
+        let mut x1 = 0;
+        let mut x2 = 0;
+        let mut mask = 0;
+
+        for num in nums {
+            x2 ^= x1 & num;
+            x1 ^= num;
+            mask = !(x1 & x2);
+            x2 &= mask;
+            x1 &= mask;
+        }
+
+        x1
+    }
+}
+// @lc code=end
+

169.majority-element.rs

@@ -0,0 +1,31 @@
+/*
+ * @lc app=leetcode id=169 lang=rust
+ *
+ * [169] Majority Element
+ */
+
+// @lc code=start
+impl Solution {
+    pub fn majority_element(nums: Vec<i32>) -> i32 {
+        let mut cnt = 1;
+        let mut val = nums[0];
+
+        for i in 1..nums.len() {
+            if val != nums[i] {
+                if cnt == 0 {
+                    val = nums[i];
+                } else {
+                    cnt -= 1;
+                }
+            } else {
+                cnt += 1;
+            }
+
+
+        }
+
+        val
+    }
+}
+// @lc code=end
+

191.number-of-1-bits.rs

@@ -0,0 +1,22 @@
+/*
+ * @lc app=leetcode id=231 lang=rust
+ *
+ * [231] Power of Two
+ */
+
+// @lc code=start
+impl Solution {
+    pub fn is_power_of_two(mut n: i32) -> bool {
+        if n == 0 {
+            return false;
+        }
+        
+        while n & 1 == 0 {
+            n >>= 1;
+        }
+
+        n == 1
+    }
+}
+// @lc code=end
+

231.power-of-two.rs

@@ -0,0 +1,29 @@
+/*
+ * @lc app=leetcode id=5 lang=rust
+ *
+ * [5] Longest Palindromic Substring
+ */
+
+// @lc code=start
+impl Solution {
+    pub fn longest_palindrome(s: String) -> String {
+        let N = s.len();
+        let chars: Vec<char> = s.chars().collect();
+
+        let mut dp = vec![vec![false; N]; N];
+        let mut ans = "";
+        for j in 0..N {
+            for i in (0..j+1).rev() {
+                if chars[i] == chars[j] && (j == 0 || i+1 >= j-1 || dp[i+1][j-1]) {
+                    dp[i][j] = true;
+                    if j - i + 1 > ans.len() {
+                        ans = &s[i..j+1];
+                    }
+                }
+            }
+        }
+        ans.to_string()
+    }
+}
+// @lc code=end
+